Alarm clock



D. W. CLARK ALARM CLOCK July 4, 1967 3 Sheets-Sheet 1 Filed Aug. 19, 1965 INVENTOR. Dona/o M [76kt gn w ATTORNEY D. W. CLARK July 4, 1967 ALARM CLOCK 3 Sheets-Sheet 2 Filed Aug. 19, 1965 INVENTOR. v

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D ha/o Pt f/an BY ATTORNEY United States Patent 3,328,952 ALARM CLOCK Donald W. Clark, Hopkinton, Mass., assignor to General Electric Company, a corporation of New York Filed Aug. 19, 1965, Ser. No. 481,032 2 Claims. (Cl. 58-16) ABSTRACT OF THE DISCLOSURE This invention relates to an alarm clock and, more particularly, to an improved bell striking mechanism for such a clock.

It is often desirable to provide an alarm clock which rings by relatively widely spaced strokes. This type alarm allows a more gradual awakening than is provided by the conventional rapid ringing alarm. Furthermore, the spaced ringing may be the first stage of a two step ringing sequence. In such a two step sequence, the spaced ringing may be followed by rapid ringing.

A number of mechanisms have been provided by the prior art to accomplish the spaced ringing of an alarm bell. However, each of these mechanisms has certain dis advantages which it would be desirable to overcome. Certain of these devices, for example, require the use of a relatively complex escapement mechanism for activating the alarm striking mechanism. Other types of alarms are spring actuated but, in these devices, certain of the moving elements are caused to strike structural portions of the clock as wel as the bell. This creates an objectionable metallic sound which is quite audible when coupled with the relatively low sound level of a small bell. In spite of this disadvantage, prior art clocks are often designed with such a feature in order to provide a mechanism in which the hammer will retract tom the bell immediately after the strike, and then be prevented from restriking until the drive mechanism positively initiates such action. Furthermore, prior art striker mechanisms often include considerable rattle due to various parts of the mechanism making and breaking contact with one another.

Accordingly, it is a primary object of the present invention to provide an improved striking mechanism for an alarm clock. Other objects are to provide such a mechanism which is simple and economical to construct, which is rattlefree, wherein the hammer mechanism makes contact only with the bell, which is self-damping and which is operated.

The manner in which these objects are achieved will be more apparent from the following description, the appended claims and the figures of the attached drawings, wherein:

FIG. 1 is an exploded isometric view of a clock mechanism in accordance with this invention, the motor and certain other portions being removed to reveal certain features of the mechanism;

FIG. 2 is a top view of an alarm clock mechanism constructed in accordance with this invention;

FIG. 3 is a cross section taken substantially along the line 3-3 of FIG. 2;

FIG. 4 is a cross section taken substantially along the line 4-4 of FIG. 2;

FIG. 5 is a left side view of the mechanism of the invention with the bell removed to disclose details of the construction;

FIG. 6 is an enlarged cross section of a portion of the mechanism of this invention; and

FIGS. 7-9 are details illustrating the operation of the striking mechanism.

The objects of this invention are achieved by incorporating into an audible alarm clock a timing movement, a bell, and a hammer lever which is pivotally mounted for rotation about an axis. A spring is positioned to normally exert resilient force against the hammer lever, the line of the force passing through the axis of rotation, the striking portion of the lever thus being spaced from the bell. An actuator which is driven by the timing movement, periodically rotates the lever to a position wherein the striking portion is further retracted from the bell, and thereafter releases the lever. This permits the spring to advance the lever through the line of force, all-owing the striking portion to strike the bell.

With particular reference to the drawings, there is illustrated an alarm clock mechanism constructed upon a framework comprising a base plate 10 and a front plate 12. The base and front plates are held in separated relationship by means of spacers 14, 14 which are staked at both ends. Mounted against the back of base plate 10, by means of insulating spacers 18 and screws 20 is a clock motor 22, including a field winding 24 and a magnetic field structure 26. The motor shaft extends through the base plate 10 and supports a drive pinion 28 which drives a standard gear train T. The output of the gear train controls the clock hands (not shown) by means of a standard center stack assembly 30 which protrudes through the front of front plate 12. The clock hands are set in the usual manner by means of a time set shaft 32 coupled to the gear train T by means of a pinion 34 and having a knurled knob 36 at its outer end.

Mounted adjacent the inner surface of front plate 12 are an alarm set gear 38 and an alarm timing gear 40. The alarm set gear 38 is securely mounted on a hollow stub shaft 42 (FIG. 6), so as to mesh with an intermediate set of gears 44 (FIGS. 1, 2) which is freely rotatable on the inner surface of the front plate 12 around the center stack assembly 30. The intermediate gear 44 is operable by an alarm set pinion 46, manually controllable from an alarm set shaft 48, which extends through base plate 10 to the rear of the clock.

From FIGS. 5 and 6 it will be observed that stub shaft 42 extends through an opening in front plate 12 and includes a circumferential flange 50 against which the alarm set gear 38 is slid-ably positioned by means of a bent friction washer 52. The outer end is of reduced diameter to form a shoulder 43 which engages the inner surface of front plate 12. The extreme end 42' of the stub shaft is riveted over to secure it in the front plate. A two diameter shaft 54 is mounted with its large end rotatably and axially movable within the hollow stub shaft 42. The alarm timing gear 40 is mounted on a hub 56 which, in turn, is secured to the shaft 54. Rotatably mounted on the smaller diameter portion of shaft 54 is a plastic gear 58 having six radially extending arms 60. The inner end 62 of shaft 54 extends through a supporting opening in base plate 10.

The alarm timing gear 40 is in mesh with the hour hand gear 64 in the gear train T. The alarm timing gear is cut and formed to provide a cam opening 66 and a short, angled camming plate 68 extending rearwardly therefrom. The alarm set gear 38 is cut and a portion bent inwardly to form an alarm cam 70 which is positioned on the same radius as the cam opening 66 in alarm timing gear 40.

The base plate 10 defines a generally rectangular opening 72 with an integral strap 74 at either end of the opening which is deformed to receive the ends of a pivot pin 76. The straps retain the pivot pin 7-6 securely against base plate and across the opening 72. A flipper plate 78 is pivotally mounted on the pivot pin 76 by means of a pair of spaced ears 80. The flipper plate 78 extends through the opening 72 and is in contact with the end- 62 of shaft 54. A portion of the flipper plate is offset and angled upwardly to form a latching tab 82.

A generally L-shaped shutoff lever 84 is pivotally mounted on the back surface of base plate 10 by means of a stud 86. One leg of the shutoff lever extends across the top of opening 72 and carries a rearwardly extending latch plate 88 which is curved upward at its end toprovide a came surface 90. The downwardly extending leg of shutoff lever 84 includes a curved inner edge 92 which is position across a further opening 94 provided in base plate 10. A curved outer edge 96 forms a circular arc having its center at the pivot point of shutoff lever 84. The edge 96 slides beneath the enlarged head of a stud 97 which is spaced from base plate 10 and retains lever 84 against the base plate.

Pivotally mounted against the inner surface of base plate 10 by means of a pivot shaft 100 is a cam lever 102. The cam lever 102 includes a main body portion and two oppositely extending radial arms. At the extremity of one of the arms there is mounted a camming pin 104 which extends rearwardly through opening 94 adjacent the curved edge 92 of the shutoff lever 84. The other leg of the cam lever also carries a rearwardly extending pin 106 upon which is fixedly mounted a bell hammer 108. Extending forwardly from the main body portion of cam lever 102 is a trigger plate 110 which is positionable in the path of the arms 60 extending outwardly from plastic gear 58. Also extending forwardly from the main body portion of cam lever 102 and above the pivot shaft 100 is a lug 112, having a peripheral groove which receives one end of a compression spring 114. The opposite end of spring 114 engages a similar peripheral groove in spacer 14'. It will be noted that, with cam lever 102 in the rest position, as shown in FIGS. 3 and 7, the lug 112, pivot shaft 100, and spacer 14' are in line with one another.

The base plate 10 includes a sideward extension 116 which is bent rearwardly to form a mounting plate 118 which sup orts a bell 120 by means of a mounting stud 122, a rubber grommet 124, a washer 126, and a screw 128.

A slot 130 is defined by base plate 10 adjacent opening 72. One side of slot 130 is cut away at its upper end to form an offset as shown in FIGS. 3 and 4. A manual shutoff plunger 132 is mounted with its forward end within the slot 130. The forward end of the plunger is bifurcated and the lower fork 134 is sprung outwardly and then inwardly at its extremity to form a spring latch tending to retain the plunger in either its outermost or innermost position. The upper fork 136 terminates in an upwardly extending keeper 138 which prevents the plunger from being completely withdrawn from the slot. Extending upwardly from the top edge of the plunger 132 is a camming projection 140 which is positioned to engage the cam surface 90 of latch plate 88 when plunger 132 is forced inwardly in slot 130. A support bracket 142 is mounted on field structure 26 (FIG. 5) and includes a slot for guiding the plunger 132 and also includes a circular opening positioned just below the slot for receiving a rearwardly extending guide lug 144 which extends rearwardly along the plunger 132 in alignment with the lower fork 134.

Operation During normal operation of the alarm clock mechanism, the shutoff plunger 132 is forced inwardly from the rear of the clock causing the camming projection 140 to raise the cam surface 90 of shutoff lever 84, thus rotating the lever clockwise, as viewed in FIG. 1, or counterclockwise, as viewed in FIGS. 3 and 4. In this rotated position, the curved edge 92 of the shutoff lever forces the camming pin 104 of the cam lever 102 upward, rotating the camming lever about its pivot shaft 100' and causing the hammer 108 to be retracted from the inner surface of hell 120. Also, during normal operation of the clock, the

alarm set gear 38 is so positioned that alarm cam 70 is not aligned with cam opening 66 in alarm timing gear 40 so that these gears remain spaced from one another by the height of the cam.

In order to activate the alarm, the alarm set gear 38 is rotated to a preselected setting by means of the alarm set shaft 48 and pinion 46 in the usual manner for setting the alarm time. The shutoff plunger 132 is then retracted toward the rear of the clock and the camming projection 140 disengages from the cam surface of shutoff lever 84. It will be remembered from the foregoing description that the alarm timing gear 40 is secured to the shaft 54, which is axially slidable in base plate 10. As the alarm timing gear 40 and alarm set gear 38 are separated by the height of the cam 70, the shaft 54 is forced to the rear so that its inner end 62 abuts against the flipper plate 78, causing it to pivot upward about the pivot pin 76. This raises the latching tab 82 against the latch plate 88 of shut-off lever 84, causing it to remain in its clockwise position (as seen in FIG. 1).

As the hour hand gear 64 continues to rotate, it advances the alarm timing gear 40 until the cam opening 66 becomes aligned with the alarm cam 70. This releases the force exerted by the inner end 62 of shaft 54 against the flipper plate 78 so that the latching tab 82 will no longer support the latch plate 88. This permits the cam lever 102 to rotate under the influence of spring 114 to its normal at rest position illustrated in FIG. 3 so that the trigger plate is positioned in line with the arms 60 of the plastic gear 58.

The plastic gear is driven from the gear train T so that each of the arms 60 sequentially engages the trigger 110, periodically tilting the cam lever 102 against the force of spring 114 to the position illustrated in FIG. 4. As each arm 60 continues past the trigger plate 110, the cam lever 102 is released. This sequence is illustrated in FIGS. 7 and 8. FIG. 7 represents the normal at rest position of cam lever 102 with the lug 112, pivot shaft 100, and spacer 14 in line. This i the natural position assumed by cam lever 102 due to the force exerted by the spring 114. The rotation of the cam lever 102 by the arm 60 is illustrated in FIG. 8. In this position it will be noted that the lug 112 is rotated away from its in-line position so that a force moment is exerted by the spring 114 about the pivot shaft 100. As soon as the trigger plate 110 is released by the arm 60, this moment exerts itself to rapidly rotate the cam lever 102 in a counterclockwise rotation. Inertia then carries cam lever 102 beyond the in-line position and the hammer 108 strikes the bell as shown in FIG. 9. The counterforce of spring 114 then returns cam lever 102 to the position of FIG. 7. Inertia may thereafter result in some slight oscillation about the in-line position. The degree of oscillation is controllable by the friction and mass distribution of the moving parts. However, the mechanism is basically self-damping. It will be noted that all the elements of the striker mechanism illustrated in FIGS. '7-9 remain in contact with one another throughout the entire striking sequence so that the only sound generated is that of the hammer 108 striking the bell. This sequence repeats itself each time one of the arms 60 releases the trigger 110 so that the bell chimes slowly at periodic intervals. In the particular plastic gear which is illustrated, the arms 60 are positioned so that the bell is struck six times, followed by a short interval, after which the ringing sequence is repeated.

In order to stop the alarm, the shutoff plunger 132 is forced inwardly from the back of the clock. This causes the camming projection to once again raise the cam surface 90 and rotate the shutoff lever 84 into contact with camming pin 104 to retract the hammer 108 from the bell.

It will now be apparent to those skilled in the art that the above described invention accomplishes all the objectives hereinbefore set forth. It will also be apparent that a number of variations and modifications may be made in this invention. Accordingly, the foregoing description is to be construed as illustrative only rather than limiting. This invention is limited only by the scope of the following claims which are to be interpreted to include all variations and modifications which fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An alarm clock comprising:

(a) a base plate;

(b) spring support means connected to said base plate;

(c) a timing mechanism including a driving gear mounted for rotation between said front plate and said base plate;

(d) a cam lever pivotally mounted on said base plate to rotate about an axis generally perpendicular to said base plate, said lever including a spring support lug arranged generally parallel to said spring support means;

(e) a single wire bow spring, said spring being formed with a bowed central portion and two generally U-shaped end portions, one of said end portions being positioned over said spring support means and the other end portion being positioned over said spring support lug so that said spring is placed under compression to apply a resilient force against said spring support lug and said cam lever in a direction extending radially outward from the pivot axis of said cam lever;

(f) trigger plat-e means integrally formed on said cam lever;

(g) rotatably mounted actuator means including an integrally formed driven gear and a plurality of radially extending arms positioned to sequentially contact said trigger plate to pivot said cam lever arm in a first direction against the force of said spring means and thereafter release said cam lever, said timing mechanism driving gear being arranged to rotate said driven gear;

(h) hammer means on said cam lever;

(i) a bell positioned to be struck by said hammer means when said cam lever is released by each of said radially extending arms, said wire bow spring resilient-1y forcing said hammer portion against said bell.

2. An alarm clock comprising:

(a) a base plate;

(b) a front plate arranged generally parallel to said base plate;

(c) a generally cylindrical spacer post positioned between said front plate and said base plate for holding said front plate in spaced relationship to said base plate;

(d) a timing mechanism including a driving gear mounted for rotation between said front plate and said base plate;

(e) a cam lever pivotally mounted on said base plate to rotate about an axis generally perpendicular to said base plate, said lever including a spring support lug arranged generally parallel to said spacer post;

(f) a single wire bow spring, said spring being formed with a bowed central portion and two generally U-shaped end portions, one of said end portions being positioned over said spacer post and the other end portion being positioned over said spring support lug so that said spring is placed under compression to apply a resilient force against said spring support lug and said cam lever in a direction extending radially outward from the pivot axis of said cam lever;

(g1) trigger plate means integrally formed on said 0am -ever;

(h) rotatably mounted actuator means including an integrally formed driven gear and a plurality of radially extending arms positioned to sequentially contact said trigger plate to pivot said cam lever arm in a first direction against the force of said spring means and thereafter release said cam lever, said timing mechanism driving gear being arranged to rotate said driven gear;

(i) hammer means on said cam lever;

(j) a bell positioned to be struck by said hammer means when said cam lever is released by each of said radially extending arms, said wire bow spring resiliently forcing said hammer portion against said bell.

References Cited UNITED STATES PATENTS RICHARD B. WILKINSON, Primary Examiner.

MICHAEL L. LORCH, GERALD F. BAKER,

Assistant Examiners. 

1. AN ALARM CLOCK COMPRISING: (A) A BASE PLATE; (B) SPRING SUPPORT MEANS CONNECTED TO SAID BASE PLATE; (C) A TIMING MECHANISM INCLUDING A DRIVING GEAR MOUNTED FOR ROTATION BETWEEN SAID FRONT PLATE AND SAID BASE PLATE; (D) A CAM LEVER PIVOTALLY MOUNTED ON SAID BASE PLATE TO ROTATE ABOUT AN AXIS GENERALLY PERPENDICULAR TO SAID BASE PLATE, SAID LEVER INCLUDING A SPRING SUPPORT LUG ARRANGED GENERALLY PARALLEL TO SAID SPRING SUPPORT MEANS; (E) A SINGLE WIRE BOW SPRING, SAID SPRING BEING FORMED WITH A BOWED CENTRAL PORTION AND TWO GENERALLY U-SHAPED END PORTIONS, ONE OF SAID END PORTIONS BEING POSITIONED OVER SAID SPRING SUPPORT MEANS AND THE OTHER END PORTION BEING POSITIONED OVER SAID SPRING SUPPORT LUG SO THAT SAID SPRING IS PLACED UNDER COMPRESSION TO APPLY A RESILIENT FORCE AGAINST SAID SPRING SUPPORT LUG AND SAID CAM LEVER IN A DIRECTION EXTENDING RADIALLY OUTWARD FROM THE PIVOT AXIS OF SAID CAM LEVER; (F) TRIGGER PLATE MEANS INTEGRALLY FORMED ON SAID CAM LEVER; (G) ROTATABLY MOUNTED ACTUATOR MEANS INCLUDING AN INTEGRALLY FORMED DRIVEN GEAR AND A PLURALITY OF RADIALLY EXTENDING ARMS POSITIONED TO SEQUENTIALLY CONTACT SAID TRIGGER PLATE TO PIVOT SAID CAM LEVER ARM IN A FIRST DIRECTION AGAINST THE FORCE OF SAID SPRING MEANS AND THEREAFTER RELEASE SAID CAM LEVER, SAID TIMING MECHANISM DRIVING GEAR BEING ARRANGED TO ROTATE SAID DRIVEN GEAR; (H) HAMMER MEANS ON SAID CAM LEVER; (I) A BELL POSITIONED TO BE STRUCK BY SAID HAMMER MEANS WHEN SAID CAM LEVER IS RELEASED BY EACH OF SAID RADIALLY EXTENDING ARMS, SAID WIRE BOW SPRING RESILIENTLY FORCING SAID HAMMER PORTION AGAINST SAID BELL. 